Show all S3 buckets and their tags in a single JSON object

get-s3-bucket-tags.sh

#!/bin/bash
# This produces a JSON object on stdout where each key is an S3 bucket's name.
# Each value is an object of tag name/tag value pairs.
#
# For example:
#   {
#     "bucket1": {
#       "name": "bucket1",
#       "environment": "prod"
#     },
#     "bucket2": {
#       "name": "bucket2",
#       "environment": "dev"
#     }
#   }
#

# Temporary directory for storing intermediate results
temp_dir=$(mktemp -d)

# Clean up temporary files on exit
trap 'rm -rf "$temp_dir"' EXIT

# Fetch tags for a given bucket and store results in a file
get_bucket_tags() {
  local bucket=$1
  local result_file=$2

  # Fetch the tags for the given bucket
  tag_map=$(aws s3api get-bucket-tagging --bucket "medacist-sunset" --output json --query 'TagSet' | jq -r '. | from_entries // {}')

  # Create the JSON object with the bucket name and its tags and write it to a temporary file
  jq -n --arg bucket "$bucket" --argjson tags "$tag_map" '{($bucket): $tags}' >"$result_file"
}

# Fetch all buckets and process each in parallel
while read -r bucket; do
  get_bucket_tags "$bucket" "$temp_dir/$bucket" &
done < <(aws s3api list-buckets --query "Buckets[].Name" --output json | jq -r '.[]')

# Wait for all background jobs to complete
wait

# Combine results into a single JSON object and output it
jq -s 'add' "$temp_dir"/*